There’s something about browsing on a smartphone that makes a minor intrusion like a pop-up ad feel like a rabid gargoyle is clawing at your windpipe. Google feels your pain, and now it’s putting web publishers who engage in intrusive tactics on death notice: Clean up your mobile web pages or risk seeing your search traffic plummet.

The company said in a blog post today that, starting in January, it will begin cracking down on the use of so-called interstitials. That’s basically when you visit a mobile web page and a pop-up or separate page appears—blocking the content you actually intended to see. While interstitials are universally detested by every person who has ever lived, publishers are using them more frequently as they seek creative new ways to monetize mobile clicks.

Google said the change won’t affect “responsible” techniques, such as smaller banner ads or pop-ups in response to a legal sign-off. Tweaks to Google’s search algorithm can have a huge impact on web traffic. A mobile-friendly update in 2015 was known in some circles as “Mobilegeddon.” CZ